@property --vw {
  syntax: '<length>';
  inherits: true;
  initial-value: 100vw;
}
@property --vh {
  syntax: '<length>';
  inherits: true;
  initial-value: 100vh;
}
:root {
  --w: tan(atan2(var(--vw), 1px));
  --h: tan(atan2(var(--vh), 1px));
}
.size-box::before{
  content: counter(w) 'X' counter(h);
  counter-reset: w var(--w) h var(--h);
  font-size: 150px;
  font-weight: 400;
  position: fixed;
  inset: 0;
  width: fit-content;
  height: fit-content;
  margin: auto;
}